Default color output for ls on OSX
Fixed incorrect overriding of ls alias on OSX which prevented producing color output
Merge pull request #3072 from minrk/streamfileno

raise UnsupportedOperation on iostream.fileno()
Merge pull request #3137 from minrk/inheritance

fix dot syntax error in inheritance diagram
Merge pull request #3141 from boxed/ls_colors_osx

Default color output for ls on OSX
Merge pull request #3144 from minrk/bower

minor bower tweaks
check zmq version at top-level kernel import

maybe someday this won't be necessary, but it is now.
move DEFAULT_STATIC_FILES_PATH to frontend.html.notebook

and move the friendly version checks to notebookapp.py

DEFAULT_STATIC_FILES_PATH is now accessible without pyzmq/tornado/jinja being importable.
If someone tries to use old pyzmq or tornado directly with handlers,
the version check won't happen, but that's probably the right thing to do anyway.
remove workarounds for no-longer-supported pyzmq versions
move check_for_zmq to utils.zmqrelated